| Summary: | 博士 === 國立臺灣大學 === 土木工程學研究所 === 97 === In this dissertation, the major concern is developing the numerical models based on the meshless method and immersed boundary techniques to apply to the irregular geometry and moving obstacles. The developed model must be able to handle the complex geometry and moving boundary in an efficient procedure. In the core of the numerical simulations, first of all, a novel meshless procedure based on the Eulerian-Lagrangian method of fundamental solutions (ELMFS) and method of particular solutions (MPS) is presented for solving the primitive variable form of the Navier-Stokes equations by using operator splitting scheme. Then, the two-roll mill flow and closed cavity flow around a harmonic oscillating cylinder at moderate Reynolds number (Re=100~400 ) are solved to demonstrate the accuracy and the robustness of this meshless procedure. During the solution procedure, there are no any unusual techniques or restrictions need to be considered in order to deal with the irregular geometry and moving boundary. Finally, in contrast with the meshless procedure, the finite-difference method (FDM) with hybrid Cartesian/immersed- boundary (HCIB) technique is proposed as another solution to provide the accurate predictions for moving boundary problem. The flexibility and robustness of the proposed HCIB FDM are examined by 3D driven cavity flow with a stationary sphere and the flow fields due to motions and collisions of immersed spheres at high Reynolds number (Re>10,000 ), which demonstrate that the HCIB FDM can be considered as an efficient numerical method in solving the moving boundary problem.
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